Shield and gauge unit for powderactuated tools



1951 R. w. HENNING 2,966,682

SHIELD AND GAUGE UNIT FOR POWDER-ACTUATED TOOLS I Filed June 3, 1954 2 Sheets-Sheet 1 IN VEN TOR.

Roberf I M Helm/n5 ATTOR/VDJ Jan. 3, 1961 R. w. HENNING 2,966,632

SHIELD AND GAUGE UNIT FOR POWDER-ACTUATED TOOLS Filed June 3, 1954 2 Sheets-Sheet 2 INVENTOR. Roberf M4 Hen/11' 7 HTTOR/VEYJ SHIELD AND GAUGE UNIT FOR POWDER- ACTUATED TOOLS Robert W. Henning, Rocky River, Ohio, assignor, by

mesne assignments, to Olin Mathieson Chemical Corporafion, a corporation of Virginia Filed June 3, 1954, Ser. No. 434,261

7 Claims. (Cl. 1-106) This invention relates to powder-actuated tools such as are used in driving pins, studs and like fastening elements into steel, concrete, masonry and the like, and more particularly to a shield and gauge unit for such a tool.

The invention has for one of its objects the provision for such a tool of a shield and gauge unit which not only has rotary movement for its use as a spacer gauge for pins, studs and like fastening elements fired from said tool but also, movement along the axis of the tool barrel. As a result, if the shield and gauge unit is used with a powder-actuated tool having angle fire control means, namely, means for preventing the firing of the tool if the axis of the tool barrel is inclined more than a relatively few degrees with respect to the surface of the material into which the pins, studs and like fastening elements are to be fired, the movement of the shield and gauge unit axially of the tool barrel compensates for or counter-acts, in part at least, the effect on angle fire control of rotary movement of the shield and gauge unit. Thus, the effectiveness of the angle fire control means of the tool remains substantially unchanged, as will hereinafter more fully appear.

A further object of the present invention 'is the provision for a powder-actuated tool of a threadedly mounted shield and gauge unit, the threaded mounting of the unit enabling it to move axially along the tool barrel axis as the unit is rotated in its use as a gauge. As a result, no separate axial adjustment of the shield and gauge unit is necessary for its compensating or counter-acting function with respect to the aforesaid angle fire control means.

A further object of the present invention is the provision for a powder-actuated tool of a shield and gauge unit which is particularly adapted for use with a powderactuated tool having a blast or gas-expansion chamber at one side of the tool barrel to substantially eliminate recoil and 'to reduce noise in the use of the tool, the present shield and gauge unit being directly mountable upon the surrounding wall of said chamber for effective and unitary association therewith. Inasmuch as the blast or gas expansion chamber is laterally oifset with respect to the axis of the tool barrel, the axis of rotation of the shield and gauge unit is correspondingly offset, as will be readily understood.

A further object of the present invention is the provision for a powder-actuated tool of a shield and gauge unit which has simple but effective means for limiting adjustable movement of the unit and for permitting, when desired, ready and convenient removal of the unit.

A further object 'of the present invention is the provision fora powder-actuated tool of a shield and gauge unit which is characterized by its structural simplicity, the economy of its manufacture, its strong and sturdy nature, and its general operating efiiciency and effectiveness.

Further objects of the present invention, and certain of its practical advantages, will be referred to in-or will be evident from the following description of one embodiment of the invention, as illustrated in the accompanying drawings, in which Fig. 1 is a side elevaticnal view of a powder-actuated tool having a shieldand gauge unit embodying thepresent invention, the unit being adjustably mounted on the surrounding wall of the laterally offset blast or gas-expansion chamber with which the tool is provided;

Fig. 2 is a similar view of said tool, with certain of its interior parts being shown in dotted lines, and with the tool so positioned that the angle of inclination of the axis of its tool barrel relative to the work is such that the angle fire control means of the tool prevents the tool from being fired;

Fig. 3 is a side elevational view of the tool in firing position, the blast or gas-expansion chamber of the tool and the present shield and gauge unit thereof being in section;

Fig. 4 is a View similar to Fig. 3 but with the shield and gauge unit in a difierent position of adjustment for gauge purposes; and

Fig. 5 is a detail cross-sectional view, on the line 5-5 of Fig. 3, for further illustration of the shield and gauge unit in its use as a gauge.

Before the embodiment of the present invention here illustrated is specifically described, it is to be understood that such embodiment is exemplary of but one form of the invention. It also is to be understood that the phraseology or terminology herein employed is for purposes of description and not of limitation, as the scope of the present invention is denoted by the appended claims.

For the disclosure of one embodiment of the present invention, there is here illustrated a powder-actuated tool of the general structural character disclosed in the copending application of Rowland I. Kopf, Robert W. Henning and Roger Marsh entitled Explosively Actuated Tools, application Serial No. 355,034, filed May 14, 1953, but which tool (the tool of the present application) embodies a blast or gas-expansion chamber of the structural character disclosed in the co-pending application of Robert W. Henning and Rowland J. Kopf entitled Powder-Actuated Tools, application Serial No. 434,262, filed June 3, 1954.

Both of the aforesaid prior applications are owned by 'the assignee of the present application, and reference to them may be had for a more complete understanding of the tools thereof. So far as description is here believed to be necessary, the tool of the present application includes a barrel 10, a breech plug 12 at the rear end of the barrel for receiving the cartridge or powder load (not shown), a firing pin 13 for detonating the cartridge or powder load, and an enclosing rear housing 14 mounted for slidable movement relative to the barrel 1G and having a hand grip 15 of pistol form protruding laterally from the rear end of the housing.

Slidably mounted in the side of the firingpin 13 is a pawl 16 which is normally projected laterally from the firing pin by spring means. Upon slidable forward movement of the housing 14 relative to the tool barrel 10, the firing pin pawl 16 is brought into engagement with the rear end of a longitudinally disposed cocking rod 17, and inasmuch as said cocking rod has a fixed position with respect to the tool barrel 10 (cocking rod 17 being secured against axial movement to a breech block 11 screwed onto the upper end of barrel 10 against a fixed stop, as disclosed in the aforesaid copending application, so that an axially rigid unit is formed from the upper end of rod 17 through breech block 11 and barrel 10 to the barrel muzzle), further forward movement of the housing 14 compresses or loads the firing pin spring 18 (Fig. 2) to thereby enable the firing pin,

when its pawl 16 is released from its retention by the cocking rod 17, to strike the cartridge or powder load for the detonation thereof.

To release the firing pin pawl 16 from its retention by the cocking rod 17, for the firing of the tool, a trigger 20 is pivotally mounted in the housing hand grip 15 and such trigger is provided with a sear 21 for cooperative releasing engagement with the firing pin pawl 16 upon actuation of the trigger. Upon slidable forward movement of the housing 14 relative to the tool barrel (the muzzle end of the barrel being at such time in engagement with the material M into which a pin, stud or like fastening element is to be fired), the firing pin pawl 16 is not only brought into engagement with the rear end of the cocking rod 17, as hereinbefore mentioned but also, the trigger sear 21 is brought into lateral alignment with said firing pin pawl 16, as in Fig. 3, provided that the axis of the tool barrel 10 is substantially normal to the surface of the material M into which the pin, stud or like fastening element is to be fired (an angle fire control of the tool which is hereinafter referred to).

To fire the tool, the trigger 20 is depressed, which causes the sear 21 thereof to depress the firing pin pawl 16 against its spring to move the pawl into firing pin 13 so that its outer end will clear cocking rod 17, with consequent release of the pawl from its retention by the cocking rod 17. This enables e theretofore compressed or loaded firing pin spring 1 to propel the firing pin forwardly into detonating engagement with the cartridge or powder load, and the consequent driving of the pin, stud or like fastening element into the material M all as will be readily understood.

The blast or gas-expansion chamber 22 of the present tool, by which recoil is substantially eliminated and noise materially reduced, is formed by a sleeve 23 surrounding the tool barrel 10 and movable relative thereto with the housing 14 with which it is suitably associated.

As here shown, the sleeve 23 is provided with a lateral offset 24 which contains the major portion of the blast or gas-expansion chamber 22, and adjacent this major portion of the chamber, the tool barrel 10 is provided with a series of forwardly inclined, longitudinally spaced gas venting ports 25. Arranged within the chamber are several transverse partitions or baffles 26, the forwardmost one of which, marked 26a, also serves as a closure for the front end of the chamber, and as shown in Figs. 3 and 4, each such partition or baflle, including the closure-forming partition or baifie 26a is located forwardly of one of the venting ports 25 so as to be struck by gas issuing therefrom. In addition, all but the forwardmost partition or baffie are provided with small, laterally spaced and longitudinally inclined baffles 27 which are located opposite the venting ports 25, with the number of the baffles 27 increasing toward the front end of the chamber or toward the muzzle end of the tool barrel, and with the size of such baffles increasing in a lateral outward direction, as shown in Figs. 3 and 4.

As best shown in Fig. 5, the lower end of the surrounding sleeve wall of the blast or gas-expansion chamber 22 is of circular form, with the axis of such circle laterally offset with respect to the axis of the tool barrel 10. Adjustably mounted on the lower end portion of such surrounding wall is the shield and gauge unit 28 of the present invention, a unit which functions as a shield for the protection of the tool operator from any flying fragments of the material M into which is fired a pin, stud or like fastening element and also from the fastening element itself if it should ricochet, and which unit further functions as a gauge in the spacing of fastening elements, in the driving thereof, varying distances from a given point on the shield and gauge unit and hence, varying distances from a given location, such as a wall, line or the like.

As best shown in Figs. 3 and 4, the shield and gauge unit comprises a simple one-piece member having a transverse wall 30 of generally dome shape in plan view (see Fig. 5) and a forwardly extending peripheral flange 31 of continuous or uninterrupted form. For the adjustable securement of the shield and gauge unit to the surrounding wall of the blast or gas-expansion chamber 22, the transverse wall 30 of such unit is provided adjacent the straight peripheral edge 32 thereof with an internally threaded circular opening 33 for the reception of the externally threaded lower end portion of the surrounding wall of said blast or gas-expansion chamber.

To limit the extent of rotary movement of the shield and gauge unit about the surrounding wall of the blast or gas-expansion chamber, a lock nut 34 is threadedly mounted on 'said Wall, a mounting which enables the shield and gauge unit to be readily removed if for any reason that is desirable, such as when the tool is being used in a corner, for example, and there is insufiicient room for the shield and gauge unit.

Due to the offset relationship of the axis of rotation of the shield and gauge unit to the axis of the tool barrel 10, the mid-point 35 of the straight peripheral edge 32 of the shield and gauge unit can be positioned, by rotary movement of the unit, varying distances from the tool barrel axis, as will be readily understood. In the position of the shield and gauge unit in Figs. 3 and 5, the tool barrel is at its maximum distance from the midpoint 35 of the unit, whereas in the position of such unit in Fig. 4, the tool barrel is at its minimum distance from said edge mid-point 35. Thus, by rotary movement of the shield and gauge unit, the straight edge point 35 of such unit can be located at any desired distance (within limits) from the tool barrel for the desired positioning of the pins, studs or other fastening elements with respect to a particular location, such as a wall or the like.

If desired and as here shown, indicia 36 may be provided on the outer surface of the surrounding wall of the blast or gas-expansion chamber for cooperation with an arrow 37 on the shield and gauge unit to thereby designate in inches and fractions thereof, for any particular setting of the unit, the particular distance between the tool barrel 10 and the unit mid-point 35, as will be readily understood.

As heretofore mentioned, the tool here illustrated, like the tool of the aforesaid application Serial No. 355,034, is provided with angle fire control means to prevent, for purposes of safety, the firing of the tool if the axis of the tool barrel is not substantially perpendicular to the surface of the material into which a pin, stud or like fastening element is to be fired. In the position of the tool in Fig. 2, the angle of inclination of the tool barrel axis is in excess of that permitted by the angle fire control for the firing of the tool and hence, in such position of the tool, it cannot be fired, for as shown in Fig. 2, the trigger sear 21 is out of lateral alignment with the firing pin pawl 16 and thus out of pawl-releasing position. The tool housing 14 has not been depressed sufficiently far over barrel 10 in Fig. 2 to bring trigger sear 21 to the Fig. 3 position into lateral alignment with firing pin pawl 16. Whether or not this lateral alignment occurs depends upon the relationship between the following axial lengths when the tool is depressed against workpiece M: (l) the overall axial length from the muzzle of barrel 10 to the tip of cocking rod 17 for establishing the location of firing pin pawl 16, and (2) the overall length from the front face of shield 28 in Figs. 2 and 3 through sleeve 23, housing 14, and pivoted trigger 20 to trigger sear 21 for establishing the location of said sear. The recited component parts making up each of these two lengths are rigidly interconnected so that each length remains constant in Figs. 2 and 3. Hence, when the muzzle of barrel 1!) protrudes a predetermined distance beyond the transverse, workpiece contacting plane of shield 28, as shown in Fig. 2, the tool cannot be fired. Also, spring 19, by pushing downwardly -on breech "block =11, always .biases the :barrel downwardly so that its muzzle extends out beyond this plane until it is overcome by depressing the tool sufiiciently far against the workpiece. Barrel and breech block 11 aremounted for axial movement as an assembly within a bore in housing 14 so that spring 19 can perform this operation. The last mentioned structure and co- .action regarding the barrel and spring in this tool is the same as in the tool disclosed in more detail in the aforesaid copending application.

One of the factors affecting the maximum degree of tilt of the tool barrel axis at which the tool can be fired is the angular or rotatable position of adjustment of the shield and gauge unit relative to the barrel. As the shield and gauge unit is angularly or rotatably adjusted in its use as a gauge from the position shown in Fig. 3 (wherein the mid-point 35 of the unit is at the maximum distance A from the tool barrel axis) to the position shown in Fig. 4 (wherein the mid-point 35 of the unit is at the minimum distance B from the tool barrel axis), and assuming that the tool is then tilted about the straight peripheral edge 32 of said shield and gauge unit an increase in the maximum permissible angle of tilt of the tool barrel axis at which the tool can be fired normally would result because of the fact that distance A is greater than distance B and that the tool cannot be fired if the barrel muzzle is located a predetermined axial distance beyond trigger sear 21 with this distance equal in length in Figs. 2, 3 and 4. If one assumes that the axial distance between shield 28 and trigger sear 21 would remain constant and therefore the barrel muzzle protrusion beyond the contacting plane remains constant, then not only the tangent of but also the permissible tilt angle will increase since distance A decreases to distance B. However, as the present shield and gauge unit is so mounted as to have both rotary and axial movement, a threaded mounting in the present embodiment of the invention, the shield and gauge unit moves forwardly along the axis of the tool barrel relative to housing 14 and trigger sear 21 as the unit is rotatably moved from its position in Fig. 3 to its position in Fig. 4, and because of such forward axial movement of the shield and gauge unit, the extent of which can be controlled by the pitch of the mounting threads in the present embodiment of the invention, the increase which otherwise would occur in the maximum axis of tilt of the gun barrel axis at which the tool can be fired is, in part at least, counter-acted or compensated for since tool firing will now be prevented if the barrel muzzle is located a shorter distance beyond the contacting plane of shield 28 because this plane has moved farther away from trigger sear 21. Hence, firing will now be prevented by a smaller muzzle protrusion beyond said plane. The reduction in this distance will reduce, at least partially, the tangent of and the permissible tilt angle otherwise increased by changing the position of the barrel muzzle from distance A to distance B. A reverse counter-acting or compensating elfect results, of course, from the rearward axial movement of the shield and gauge unit relative to housing 14 as such unit is rotatably or angularly adjusted from the position of Fig. 4 to the position of Fig. 3, the rearward axial movement of the unit counteracting or compensating for, in part at least, the increase of the distance A over that of the distance B. Thus, by the use of a shield and gauge unit having both axial and rotary movements, the maximum angle of tilt of the tool barrel axis at which the tool can be fired remains substantially constant as the shield and gauge unit is rotatably or angularly adjusted relative to the tool barrel, in its use as a gauge, all as will be readily understood.

From the foregoing description of one embodiment thereof, it will be evident that shield and gauge units embodying the present invention have many important features and advantages. Structurally, they are simple, inexpensive and rugged. Functionally, they are eifective shields for the protection of the tool operator and eifective gauges in the placement of the pins, studs and likefastening devices definite distances from particular reference points, such as walls and the like. In preferred embodiments, which include the one here illustrated, the shield and gauge units have axial movement as Well as rotary movement, with the axial movement thereof counter-acting or compensating for, in part at least, the increase which otherwise would result, from rotary movement of the units, in the maximum angles of tilt of the tool barrel axes at which the tools could be fired. A further feature of preferred embodiments of the invention, such as the here illustrated shield and gauge unit, is the manner in which such units can be cooperatively and unitarily associated with the blast or gas-expansion chambers of powder-actuated tools, particularly chambers which are laterally oifset from the tool barrels. As in the present embodiment of the invention, the offsetting of the shield and gauge units with respect to the tool barrels is effected by mounting such units on the walls of the offset blast or gas-expansion chambers, particularly the surrounding walls of such chambers, so that such mountings are simple, convenient and readily made.

To those skilled in the art to which the present invention relates, other features and advantages of such invention will be obvious.

What is claimed is:

1. In a powder-actuated tool having a barrel, wall means defining a blast or gas-expansion chamber for the reduction of recoil and noise, means operatively associating the barrel and said wall means effective to ofiset said chamber laterally of the barrel axis, and a protective shield and distance gauge unit rotatably mounted on said chamber wall, the lateral offset disposition of said chamber relative to the tool barrel axis resulting in a lateral olfsetting in the disposition of said shield and gauge unit, the axis of rotation of said gauge unit being laterally offset with respect to the bore axis of said tool barrel, whereby such unit by rotary adjustment thereof can function as a distance gauge for pins, studs and like fastening elements which are fired through the tool barrel in use of the tool.

2; In a powder-actuated tool having a barrel, wall means surrounding said barrel and defining a blast or gasexpansion chamber for the reduction of recoil and noise, said surrounding chamber wall having a laterally offset portion, and a protective shield and distance gauge unit rotatably mounted on said surrounding chamber wall, the axis of rotation of said unit being thus laterally 'oifset relative to the axis of the tool barrel, whereby such unit by rotary adjustment thereof can function as a distance gauge for pins, studs and like fastening elements which are fired through the tool barrel in use of the tool.

3. The tool of claim 2 wherein the barrel has a muzzle adapted to abut a workpiece and carries a charge of actuating powder and the chamber wall includes a rearwardly biased barrel housing with an axially and laterally extending portion adjacent the barrel muzzle formed by the protective shield and gauge unit, said housing being axially movable with respect to said barrel until said housing portion is also put into abutment with said workpiece, whereat said barrel is movable relative to said housing to project said muzzle forwardly of said portion when said barrel is tilted with respect to said workpiece, said housing carrying powder firing means responsive to said relative axial movement between a rearward and forward safety position of said housing and barrel, when too tilted, respectively whereat said means is in inoperative relationship with respect to said charge and forward and rearward ready-to-fire position of said housing and barrel respectively whereat said means and charge is in operable relationship with said charge, and wherein said unit provides distance gauging by a laterally adjustable peripherial edge included in said lateral portion of the housing and the rotatable mounting of said unit on said housing is adapted to simultaneously adjust said units axial extension, thereby modifying the projection of said muzzle and concomitantly modifying the angle of permissible tilt of said barrel about part of said edge as predetermined by said relative axial movement and responsive firing means, said axial adjustment of the unit being effective to select the permissible angle of tilt and to compensate for variation from said angle resulting from rotation of said unit with reference to the resultant variation in the lateral extension of said part of its peripherial edge.

4. In a powder-actuated tool having a barrel, Wall means surrounding said barrel and defining a blast or gasexpansion chamber for the reduction of recoil and noise, the lower end of said surrounding chamber wall being of circular form with the axis thereof laterally offset relative to the axis of said tool barrel, and a protective shield and distance gauge unit rotatably mounted on the lower end of said surrounding chamber Wall, whereby rotary movement of said unit about said axis laterally offset relative to the axis of the tool barrel enables such unit to function as a distance gauge for pins, studs and like fastening elements which are fired through the tool barrel in use of the tool.

5. In a powder-actuated tool having a barrel, wall means surrounding said barrel and defining a blast or gas-expansion chamber for the reduction of recoil and noise, the lower end of said surrounding chamber wall being of circular form, with the axis thereof laterally oifset relative to the axis of said tool barrel, and a protective shield and distance gauge unit threadedly mounted on said surrounding chamber Wall for rotary movement relative thereto, whereby rotary movement of said unit about the axis of the lower end of said chamber wall enables such unit to function as a distance gauge for pins, studs and like fastening elements which are fired through the tool barrel in use of the tool.

6. In a powder-actuated tool having a barrel, wall means surrounding said barrel and defining a blast or gas-expansion chamber for the reduction of recoil and noise, the lower end of said surrounding chamber wall being of circular form, with the axis thereof laterally offset relative to the axis of said tool barrel, a protective shield and distance gauge unit threadably connected with said wall means to enable said unit to have rotary movement about an axis laterally oifset relative to the axis of the tool barrel being effective to carry said unit with adjustment axially along said wall means, said rotary movement of said unit being operable to locate a part thereof in predetermined spaced relation to the axis of said unit whereby said part is utilized as a gauge means for locating said barrel in corresponding spaced relation on a workpiece having a portion adapted to engage with said gauge means, said wall means and said barrel being relatively movable against said workpiece to actuate said tool to a firing position, said tool being tiltable on said workpiece a predetermined angle of inclination about said unit to permit said barrel to project forwardly of the latter and thus de-actuate said tool to a safety position, and said axial adjustment of said unit being effective to selectively change the angle of inclination at which said tool is de-actuated to said safety position.

7. In a powder-actuated tool having a barrel, wall means surrounding said barrel and defining a blast or gas-expansion chamber for the reduction of recoil and noise, the lower end of said surrounding chamber wall being of circular form, with the axis thereof laterally offset relative to the axis of said tool barrel, a protective shield and distance gauge unit, and means for mounting such unit on said chamber wall means for rotary movement of the unit about an axis laterally offset relative to the axis of the tool barrel being effective to carry said unit with adjustment axially along said wall means, said rotary movement of said unit being operable to locate a part thereof in predetermined spaced relation to the axis of said unit whereby said part is utilized as a gauge means for locating said barrel in corresponding spaced relation on a workpiece having a portion adapted to engage with said gauge means, said wall means and said barrel being relatively movable against said workpiece to actuate said tool to a firing position, said tool being tiltable on said workpiece a predetermined angle of inclination about said unit to permit said barrel to project forwardly of the latter and thus de-actuate said tool to a safety position, and said axial adjustment of said unit being effective to selectively change the angle of inclination at which said tool is de-actuated to said safety position.

References Cited in the file of this patent UNITED STATES PATENTS 2,675,546 Catlin Apr. 20, 1954 2,679,645 Erickson June 1, 1954 2,771,607 Skumawitz Nov. 20, 1956 2,773,259 Broughton et al Dec. 11, 1956 FOREIGN PATENTS 505,746 Belgium Sept. 29, 1951 

